Stone: NSA metadata program captures small fraction of calls

Contrary to public perceptions, the National Security Agency's controversial program to collect information on phone calls to, from and within the U.S., gathers such metadata on only a small percentage of U.S. telephone traffic, a member of President Barack Obama's surveillance review group said Thursday.

"In fact, the NSA collects a very small percentage of our phone logs," University of Chicago Professor Geoffrey Stone said during a symposium sponsored by the advocacy group Public Citizen. "The numbers it collects are effectively randomly collected…They do it by service provider. If you happen to use a service provider who participates in their program, you're number might get picked up. If you use another company, your number won't get picked up."

Stone did not specify which providers are involved in the program, which is aimed at preventing terrorist attacks. He also said he could not disclose the precise percentage of calls about which the NSA collects data.

Stone noted during his remarks that the review group's report, which was released publicly last month, says that the program's scope is limited.

“The meta-data captured by the program covers only a portion of the records of only a few telephone service providers,” the report says.

Stone said that due to secrecy rules the review group was unable to say precisely how much calling data the government collects. "We can’t use the number because it’s classified. It shouldn't be, but it is," he said.

The reason for the partial coverage is financial, the professor said.

"Basically, they said it’s very expensive" to gain greater coverage of call data," Stone said. "One argument you could make about this is if it's not worth spending the money to get 100% then it's not worth doing at all."

Initial news reports following leaker Edward Snowden's revelation of the so-called Section 215 program in June said that the NSA effort collects the bulk of U.S. calling data. Opinions from the Foreign Intelligence Surveillance Court say the program collects data on "substantially all" calls handled by telephone companies. However, the rulings don't say whether all companies are involved, beyond a particular Verizon affiliate.

UPDATE (Thursday, 1:14 P.M.): This post has been updated with Stone's remarks on the costs of the program.